"Roy Lewallen" wrote
I tried really hard to say clearly that I'm speaking
of transmission
lines and not one- or two-port analysis.

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There's no difference between the two. If you produce
the symetrical S-matrix for a length of transmission
line, its 4 parameters contain complex hyperbolic
functions like (Ro+jXo)*Cosh(A+jB) . . . . . where A
is nepers and B is radians.

Whichever way you go, matrix-algebra or Heaviside, you
perform exactly the same set of calculations and, not
surpisingly, you end up with the same answers -
provided Zo in one place only is not followed with an
askerisk just to obtain another answer which is thought
to be more preferable.
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Reg, G4FGQ